Shield for explosive cutter

ABSTRACT

A blast shield formed as a multilayer sandwich of composite material configured to provide protection to bystanders in close proximity to operation of a linear shaped charge. An exemplary embodiment may be used to shield passengers when explosively cutting an emergency door in airliners. The composite material forming a blast shield may have two types of composition: the first type contains a layer of carbon fiber cloth, a layer of natural rubber and a layer of Kevlar fiber cloth, from the inside out in order. The second type contains a layer of carbon fiber cloth, a layer of Kevlar fiber cloth and a layer of polyurethane rubber, from the inside out in order. Both types typically use epoxy resin as the bond between each layer. Through the composition of fiber and rubber, embodiments can effectively block the spread of explosive shock waves, reduce the noise, decrease the weight of protective devices, and avoid forming wounding debris. When applied on the surface of a linear shaped charge, the blast shield can limit the explosive sub-effect to the minimum, which meets the features of aircraft cabin which has limited space and multiple passengers.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of the filing date of China National Invention Patent Application No. 200910025066.5, for “Composite Material for Protective Layer of Shaped Cutter of Emergency Door on Airliners”, filed on Feb. 16, 2009, the entire contents of which are hereby incorporated by this reference.

BACKGROUND OF THE INVENTION

1. Field

This invention relates generally to blast shields, and particularly to a blast shield configured to resist infliction of damage to a human disposed within proximity to a linear shaped explosive charge during detonation of that charge to form an emergency exit from a confined space.

2. State of the Art

It is known to use linear charges to cut through certain objects. For example, it is believed that the United States military employs linear shaped explosive charges to form emergency exits from experimental aircraft. However, those devices lack sufficient blast shielding as to permit a human to remain in close proximity (e.g. 0.2 to 1.5 m) to the detonated charge when forming the emergency exit.

It would be an improvement to provide a blast shield, which may be used even in commercial aircraft, to permit forming an emergency exit door from the airplane while an undamaged human passenger remains in close proximity to the door-cutting device.

BRIEF SUMMARY OF THE INVENTION

Embodiments structured according to certain principles if the invention provide a blast shield that is effective to attenuate undesired sub-effects from the detonation of a shaped explosive charge sufficient to resist damage to a human that is within a distance of more than about 0.4 m of the explosive charge during its detonation. Preferred embodiments are structured as multi-layered sandwiches including first, second, and third layers. The first layer, second layer, and third layer may be individually sized in thickness and configured and arranged in harmony to protect a bystander from a selected linear shaped charge having a given explosive energy.

A workable first layer includes a non-metallic layer disposable to substantially cover a first area encompassing a shaped explosive charge of the type that may be used to cut through an object. Preferably, the first layer is formed from a material having high strength and high temperature resistance. One workable first layer is formed from carbon fiber. In a currently preferred embodiment, the first layer is formed from carbon fiber cloth and has a thickness of about 2 mm. Sometimes, a first layer includes layers of carbon fiber cloth arranged to form a quasi-isotropic laminate.

A workable second layer includes a non-metallic layer sized to substantially cover the first area and disposed above the first layer. Desirably, the second layer is formed from a material having outstanding flexibility. One workable second layer is formed from natural rubber. One workable second layer may be formed from natural rubber having a thickness between about 1.5 and 2 mm. An alternative second layer may be formed from polyurethane rubber. The alternative second layer in a preferred embodiment is formed from polyurethane rubber having a thickness of about 26 mm.

A workable third layer includes a non-metallic layer sized to substantially cover the first area and disposed above the first layer. Desirably, the third layer is formed from a material having high strength and high toughness. One workable third layer is formed from aramid, or aramid-based, fiber. The third layer in a currently preferred embodiment is formed from aramid, or aramid-based, fiber cloth and has a thickness of about 1.5 mm. Sometimes, a third layer includes layers of aramid, or aramid-based, fiber cloth arranged to form a quasi-isotropic laminate.

Sometimes, the second layer is disposed between the first layer and the third layer. Other times, the third layer is disposed between the first layer and the second layer. An area of the first layer may be bonded to one of the second layer and the third layer by way of epoxy resin; and an area of the second layer may be bonded to the one of the first layer and third layer by way of a binder, such as epoxy resin. Typically, an area of the first layer is bonded to the object to be cut by way of a binder, such as epoxy resin.

A first currently preferred embodiment includes a first layer that is formed from carbon fiber cloth and has a thickness of 2.0±0.1 mm. The second layer of that embodiment is formed from natural rubber having a thickness between about 1.5 mm and 2.0 mm. The third layer of that embodiment is formed from aramid, or aramid-based, fiber cloth and has a thickness of 1.5±0.1 mm.

A second currently preferred embodiment has a first layer that is formed from carbon fiber cloth and has a thickness of 2.0±0.1 mm. A third layer that is bonded on top of the first layer is formed from aramid, or aramid-based, fiber cloth and has a thickness of 1.5±0.1 mm. A second layer, bonded on top of the third layer, is formed from polyurethane rubber having a thickness of about 26 mm.

In certain embodiments, the object to be cut is structure of an airplane, and the shaped explosive charge is configured and arranged to cause a door opening sized to permit an emergency escape of a human from inside the airplane. Sometimes, an area of the first layer is bonded to the second layer by way of epoxy resin. Also, an area of the second layer may be bonded to the third layer by way of epoxy resin. Further, an area of the first layer may be bonded to the object by way of epoxy resin.

The invention may be embodied to form a blast shield. A first exemplary embodiment may include a non-metallic first layer disposable to substantially cover a first area encompassing a shaped explosive charge of the type that may be used to cut through structure of an airplane effective to form an emergency exit door. That first layer is desirably formed from high strength and high temperature resistance carbon fiber cloth arranged to form a quasi-isotropic laminate having a thickness of about 2 mm, an area of that first layer being bonded to the structure to be cut by way of epoxy resin. The first embodiment also includes a non-metallic second layer sized to substantially cover the first area and being bonded to the first layer by way of epoxy resin, the second layer consisting of natural rubber. The first embodiment also includes a non-metallic third layer sized to substantially cover the first area and being bonded to the second layer by way of epoxy resin, the third layer being formed from high strength and high toughness aramid, or aramid-based, fiber cloth arranged to form a quasi-isotropic laminate having a thickness of about 1.5 mm. The first layer, second layer, and third layer are configured and arranged in harmony such that the blast shield is effective to attenuate sub-effects from the detonation of the shaped explosive charge sufficient to resist damage to a human that is within a distance of about one-half meter of said explosive charge during the detonation.

A second exemplary embodiment of a blast shield includes a non-metallic first layer disposable to substantially cover a first area encompassing a shaped explosive charge of the type that may be used to cut through structure of an airplane effective to form an emergency exit door. That first layer being formed from high strength and high temperature resistance carbon fiber cloth arranged to form a quasi-isotropic laminate having a thickness of about 2 mm, an area of the first layer being bonded to the structure to be cut by way of epoxy resin. The second embodiment includes a non-metallic third layer sized to substantially cover the first area and being bonded to the first layer by way of epoxy resin. That third layer being formed from high strength and high toughness aramid, or aramid-based, fiber cloth arranged to form a quasi-isotropic laminate having a thickness of about 1.5 mm. The second embodiment also includes a non-metallic second layer sized to substantially cover the first area and being bonded to the top of the third layer by way of epoxy resin, the second layer consisting essentially of a rubber material. The first layer, second layer, and third layer are configured and arranged in harmony such that the blast shield is effective to attenuate sub-effects from the detonation of the shaped explosive charge sufficient to resist damage to a human that is within a distance of about one-half meter of the explosive charge during the detonation.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a view in perspective of a first embodiment structured according to certain principles of the instant invention;

FIG. 2 is a view in perspective of a second embodiment structured according to certain principles of the instant invention; and

FIG. 3 is cross-section view in elevation of an embodiment structured according to certain principles of the invention installed in association with a linear shaped charge and on an object to be cut.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Reference will now be made to the drawings in which the various elements of the illustrated embodiments will be given numerical designations and in which the invention will be discussed so as to enable one skilled in the art to make and use the invention. It is to be understood that the following description is only exemplary of the principles of the present invention, and should not be viewed as narrowing the claims which follow.

For purpose of this disclosure, the term “high strength and high temperature resistance” is intended to mean ultimate tensile strength of no less than 10 thousand PSI and the ability to survive no lower than 3500 Celsius degrees for the time duration of a detonation event. Further, “high strength and high toughness” is intended to mean the material can withstand an impact having a certain level of energy without failure (as for Kevlar fiber, tenacity is 20.92 cN/ditex). “Outstanding elasticity” means the material can stretch by a considerable amount without rupture (as for natural rubber, the elastic modulus is 3-6 MPa, elastic elongation can reach 1000%). The phrase “to attenuate undesired sub-effects from the detonation of a shaped explosive charge sufficient to resist damage to a human” is defined as reducing blast sub-effect to that which a human can tolerate. The extra pressure (over 1 PSI) a human being can tolerate is no bigger than 0.2 PSI and the result from the test is 0.08 PSI at maximum. The noise a human being can tolerate is 180 dB and the result from the test was 110 dB.

Embodiments of a blast shield structured according to certain principles of the instant invention provide protection to bystander(s) from shock waves, noise, metal flying debris, etc., which may be generated by a linear shaped explosive charge of the type that may be used to cut through an object. Preferred embodiments permit use of such a shaped explosive cutter in commercial aircraft to form an emergency escape door. Such embodiments permit the emergency door to be formed, within a 0.2-1.5 m range between bystander(s) and the cutting device, without causing damage to the bystander(s). A workable blast shield provides a safe, reliable, and efficient comprehensive protection layer formed as a multilayer composite material. Elements, or component layers, of an individual blast shield may be sized based on the features, or explosive characteristics, of particular shaped explosive charge cutters. Blast shields structured according to certain principles of the invention may also be applied to safety protection of personnel under other similar environments for implementation of the blasting operation.

Effective design of a workable blast shield may be based on an understanding of explosive sub-effect features of a linear shaped explosive charge cutter. A workable blast shield operates by attenuation of undesired sub-effects through the solid media forming the shield. Desirably, non-metallic materials are used to form the protective layer, or blast shield, in order to achieve comprehensive protection to bystanders from undesired explosive sub-effects including shock wave and noise, and also to prevent flying metal fragments that may be spawned from the blast shield as a result of detonation of the linear shaped charge. In order to achieve the complementary roles of non-metallic materials, we use materials such as carbon fiber cloth which can endure high-strength and high temperature, natural or synthetic rubber which has outstanding flexibility, and aramid, or aramid-based, fiber cloth (e.g. Kevlar™) which has high strength and high toughness, and use epoxy resin as binder to compose this protective layer composite material.

Carbon fiber cloth, aramid, or aramid-based, fiber cloth and natural or synthetic rubber have different material properties. Therefore, a blast shield may be structured, at least in-part, according to the structure and shape of the object being cut, and available space in which the shield may fit. Two exemplary embodiments of a blast shield are disclosed below as protective layer composite material, Class A and Class B, respectively.

Class A protective layer composite material includes three layers from the inside out in order: a layer of carbon fiber cloth, a layer of natural rubber and a layer of aramid, or aramid-based, fiber cloth. Epoxy resin is coated between each layer to form a composite layer (blast shield) composed of four kinds of materials. The thickness of a workable layer of carbon fiber cloth is 2.0±0.1 mm, and this layer is a laminate of two plies of carbon fiber cloth which have a 45° cross to improve the behavior of the protective layer from all directions. It should be noted that other laminate orientations are also workable. However, it is currently preferred to form the carbon fiber layer as a quasi-isotropic laminate layer. The thickness of a workable layer of natural rubber is 1.5-2.0 mm. The thickness of a workable layer of aramid, or aramid-based, fiber cloth is 1.5±0.1 mm, and this layer is also desirably formed by two plies of aramid, or aramid-based, fiber cloth disposed to form a 45° cross. Epoxy resin has good adhesion properties on all three kinds of materials, thus it makes this composite material have good forming and solidification performance, and enhances the connection between the warp and weft of fiber cloth, which helps the overall mechanical properties of the fabric and resulting blast shield.

Desirably, the high-strength and high-temperature layer of carbon fiber cloth is disposed in the most inner layer (closest to the linear shaped explosive charge), because the shaped charge generates not only shock wave, but also high-temperature gas. Natural or synthetic rubber and carbon fiber cloth have different wave impedance, thus they favor the shock and attenuation of the shock waves in these two layers of different materials. The laminate layer of aramid, or aramid-based, fiber cloth not only resolves the lacking of strength and toughness of natural rubber, but also has different wave impedance. In addition to improving the bonding strength of the above three materials, the epoxy resin also has a certain effect in reducing noise.

According to explosive loading dose of the linear shaped explosive charge cutter, Class A protective layer can be used by either as single-layer or multiple layers. That is, multiple layers may be used in the case(es) where a shaped charge is more energetic. Protective layers of Class A material may simply be stacked to increase the protective capacity of the resulting blast shield. Thickness of any layer, and/or all layers, may also be adjusted to achieve a blast shield that provides sufficient protection capacity when used with a particular linear shaped charge cutter.

Class B protective layer composite material includes three layers from the inside out in order: a layer of carbon fiber cloth, a layer of aramid, or aramid-based, fiber cloth and a layer of polyurethane rubber. Epoxy resin is coated between each layer to form a composite material composed of four kinds of materials. The thickness and composition of the layers of carbon fiber cloth and aramid, or aramid-based, fiber cloth may be the same as described in the Class A type of material, while the thickness of the layer of polyurethane rubber is typically determined according to the structural features of the object being cut.

Class B composite material can be used when the installation and fixed space are severely restricted, and polyurethane rubber is required to make into a fixed body.

A protective layer (blast shield) made from either Class A or Class B composite material makes full use of lightweight high-strength characteristics of fiber. It helps to reduce the weight of protective devices. It may create a smaller body and a beautiful shape. Compared with the use of metal protective material, preferred embodiments of the instant invention will not form wounding fragments. With the combination of fiber and rubber, this composite material effectively blocks the spread of explosive shock waves and reduces noise. When applied on the shaped cutter surface, the protective layer composite material can limit the undesired explosive sub-effect to the minimum, which meets the features of aircraft cabin which has limited space and multiple passengers.

A workable material for a layer having high strength and high temperature resistance layer includes TOHO carbon fiber biaxial HTA-3k commercially available from TOHO Chemical Industry Co., LTD, Japan. A workable aramid, or aramid-based fiber material for a layer having high strength and high toughness includes Kevlar™ K29 from DuPont. A workable material for forming a layer having outstanding flexibility includes natural rubber available in local industrial material vendor. An alternative workable material for forming a layer having outstanding flexibility includes a synthetic rubber (e.g. polyurethane), available in local industrial material vendor. A workable epoxy resin (6101) can be bought at local industrial material vendor.

Specific Implementation Modalities

Example 1

With reference to FIG. 1, Class A protective layer composite material includes three layers, which are a layer 11 formed as a laminate of carbon fiber cloth, a layer 12 of natural rubber and a layer 13 formed as a laminate of aramid, or aramid-based, fiber cloth. The illustrated arrangement is described from the inside out, in order. A binder, such as an epoxy resin (e.g. 6101 epoxy resin), is typically coated between each layer to form a composite multi-layer sandwich protective layer (blast shield) including four kinds of materials.

For the exemplary embodiment of a blast shield used in this test, the carbon fiber cloth layer thickness was 2.0±0.1 mm, and it was formed by two layers of carbon fiber cloth which have a 45° cross (e.g. a quasi-isotropic layup of fibers oriented at 0, 90, +45, and −45 degrees) to improve the behavior of the protective layer from all directions. The natural rubber layer was 1.5-2.0 mm in thickness. The aramid, or aramid-based, fiber cloth layer was 1.5±0.1 mm in thickness, and it was also formed by two layers of Kevlar™ fiber cloth which have a 45° cross. 6101 epoxy resin has good adhesion properties on all three kinds of materials, thus it makes this composite material have good forming and solidification performance, while enhances the connection between the warp and weft of fiber cloth, which helps the overall mechanical properties of the fabric and resulting blast shield.

For this test, the Class A protective layer composite material was applied over a linear shaped charge and on a portion of a Chinese-made ARJ21-700 aircraft's fuselage skin. The selected flexible linear shaped charge cutter has sufficient explosive energy to cut the fuselage skin at 2.0 mm depth. The explosive linear charge cutter was arranged to make a rectangle with length at 140 mm and width at 120 mm. When detonated, it formed a total of four incisions to create a sub-scale door opening. The Class A protective layer composite material was applied and cured according to conventional techniques. It has been found that the linear shaped charge may be adhered to the blast shield using AB two part Epoxy glue. The test arrangement is illustrated in FIG. 3, with the blast shield 16 installed over linear shaped charge 17. The object being cut is identified by numeral 18. Of note, the blast shield 16 is penetrated by a small initiator access port 19.

The test results indicated that the protective layer composite material forming the blast shield 16 effectively blocked the spread of explosive shock waves and reduced noise. Test results showed a maximum decibel level at 0.4 meter distance was 110 dB, extra pressure caused by shock wave at 0.4 meter distance was 0.08 PSI. Non-metallic debris should not cause harm to human.

The distance from the test linear charge to measurement equipment was 0.4 meters. This distance is not really closely related to the explosive amount used on different situations, because different numbers of the protective layers (blast shield 16) may be stacked based on the required load density. Load density can be defined as grams of explosive per meter. When the density is smaller than 3 g/m, a single blast shield will suffice. When load density is between 3 to 20 g/m, we form a blast shield from a stack of two layers of Class A protective layer composite material. When it is between 20 to 80 g/m, we use three layers. Example 1 has average of 2.6 g/m density and we used one layer of the composite shield. Example 2 and 3 have average of 19-21 g/m density and we used two layers. We also did higher amount density when we cut 20 mm thick steel plate, in which case the density is 60-80 g/m and three layers of protective material was used.

Example 2

In this test, multi-layer composite material forming a blast shield was applied on the Chinese-made ARJ21-700 passenger service module door hinge plate, and cured according to conventional techniques. The hinge plate is made from aviation grade aluminum and the cross-section size at the cutting location was 70×15.9 mm. The thickness of the hinge plate that the Flexible Linear Shaped Cutter used can cut is 8.0 mm. Cutting devices were therefore arranged face to face on both sides of the hinge plate. The length of the linear shaped charge cutting device was 2×70 mm. Class A protective layer composite material having the same configuration and arrangement as was used in example 1 was again used in this case.

The test results indicated that the protective layer composite material forming the blast shield 16 effectively blocked the spread of explosive shock waves and reduced noise.

Example 3

A blast shield formed as multi-layer composite material was applied as explosive cutting protection of a passenger door lock on the Chinese-made ARJ21-700. The lock is made from high-strength aerospace aluminum alloy material. The cross-section of the lock to be cut has a groove shape. The thickness of the lock's upper flange, sidewall and lower flange are 4 mm, 6 mm and 3 mm, respectively. The cutting capacity of the selected flexible linear shaped charge cutting device is 6.0 mm thickness of the aluminum alloy plate. As the installation space of the cutting device is severely restricted, the blast shield was formed from Class B type of protective layer composite material, with the carbon composite material being disposed in a close fitting arrangement with the shaped explosive's surface.

With reference to FIG. 2, a blast shield formed from Class B protective layer composite material includes three layers, which are carbon fiber cloth layer 11, Kevlar™ fiber cloth layer 13 and polyurethane rubber layer 15 from the inside out. A binder, such as 6101 epoxy resin 14, is coated between each layer to form a composite sandwich comprising four kinds of materials. The thickness and composition of the carbon fiber cloth layer and the Kevlar fiber cloth layer were the same as described in the Class A type of material. The thickness of the layer of polyurethane material 15 was about 26.1 mm.

The test results proved that the protective layer composite material effectively blocked the spread of explosive shock waves, reduced noise and prevented undesired back-splash of the residual jet of explosive byproducts from the shaped charge.

While the invention has been described in particular with reference to certain illustrated embodiments, such is not intended to limit the scope of the invention. The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

1. A blast shield, comprising: a non-metallic first layer disposable to substantially cover a first area encompassing a shaped explosive charge of the type that may be used to cut through an object, said first layer being formed from a material having high strength and high temperature resistance; a non-metallic second layer sized to substantially cover said first area and disposed above said first layer, said second layer being formed from a material having outstanding elasticity; and a non-metallic third layer sized to substantially cover said first area and disposed above said first layer, said third layer being formed from a material having high strength and high toughness, wherein: said first layer, said second layer, and said third layer are individually sized in thickness and are configured and arranged in harmony such that said blast shield is effective to attenuate sub-effects from the detonation of said shaped explosive charge sufficient to resist damage to a human that is within a distance of about 0.4 meter of said explosive charge during said detonation.
 2. The blast shield according to claim 1, wherein: said first layer is formed from carbon fiber.
 3. The blast shield according to claim 1, wherein: said second layer is formed from natural rubber.
 4. The blast shield according to claim 1, wherein: said second layer is formed from polyurethane rubber.
 5. The blast shield according to claim 1, wherein: said third layer is formed from aramid, or aramid-based, fiber.
 6. The blast shield according to claim 1, wherein: said first layer is formed from carbon fiber cloth and has a thickness of about 2 mm; said second layer is formed from natural rubber having a thickness between about 1.5 and 2 mm; and said third layer is formed from aramid, or aramid-based, fiber cloth and has a thickness of about 1.5 mm.
 7. The blast shield according to claim 6, wherein: said second layer is disposed between said first layer and said third layer.
 8. The blast shield according to claim 1, wherein: said first layer is formed from carbon fiber cloth and has a thickness of about 2 mm; said second layer is formed from polyurethane rubber having a thickness of about 26 mm; and said third layer is formed from aramid, or aramid-based, fiber cloth and has a thickness of about 1.5 mm.
 9. The blast shield according to claim 8, wherein: said third layer is disposed between said first layer and said second layer.
 10. The blast shield according to claim 1, wherein: an area of said first layer is bonded to one of said second layer and said third layer by way of epoxy resin; and an area of said second layer is bonded to the one of said first layer and said third layer by way of epoxy resin.
 11. The blast shield according to claim 10, wherein: an area of said first layer is bonded to said object by way of epoxy resin.
 12. The blast shield according to claim 7, wherein: said first layer is formed from carbon fiber cloth and has a thickness of 2.0±0.1 mm; said second layer is formed from natural rubber having a thickness between 1.5 and 2.0 mm; and said third layer is formed from aramid, or aramid-based, fiber cloth and has a thickness of 1.5±0.1 mm.
 13. The blast shield according to claim 9, wherein: said first layer is formed from carbon fiber cloth and has a thickness of 2±0.1 mm; said second layer is formed from polyurethane rubber having a thickness of about 26 mm; and said third layer is formed from aramid, or aramid-based, fiber cloth and has a thickness of 1.5±0.1 mm.
 14. The blast shield according to claim 1, wherein: said first layer comprises layers of carbon fiber cloth arranged to form a quasi-isotropic laminate; and said third layer comprises layers of aramid, or aramid-based, fiber cloth arranged to form a quasi-isotropic laminate.
 15. The blast shield according to claim 11, wherein: said object is structure of an airplane; and said shaped explosive charge is configured and arranged to cause a door opening sized to permit an emergency escape of a human from inside said airplane.
 16. The blast shield according to claim 15, wherein: an area of said first layer is bonded to said second layer by way of epoxy resin; an area of said second layer is bonded to said third layer by way of epoxy resin; and an area of said first layer is bonded to said object by way of epoxy resin.
 17. A blast shield, comprising: a non-metallic first layer disposable to substantially cover a first area encompassing a shaped explosive charge of the type that may be used to cut through structure of an airplane effective to form an emergency exit door, said first layer being formed from high strength and high temperature resistance carbon fiber cloth arranged to form a quasi-isotropic laminate having a thickness of about 2 mm, an area of said first layer being bonded to said structure by way of epoxy resin; a non-metallic second layer sized to substantially cover said first area and being bonded to said first layer by way of epoxy resin, said second layer consisting of natural rubber; and a non-metallic third layer sized to substantially cover said first area and being bonded to said second layer by way of epoxy resin, said third layer being formed from high strength and high toughness aramid, or aramid-based, fiber cloth arranged to form a quasi-isotropic laminate having a thickness of about 1.5 mm, wherein: said first layer, said second layer, and said third layer are configured and arranged in harmony such that said blast shield is effective to attenuate sub-effects from the detonation of said shaped explosive charge sufficient to resist damage to a human that is within a distance of about 0.4 meter of said explosive charge during said detonation.
 18. A blast shield, comprising: a non-metallic first layer disposable to substantially cover a first area encompassing a shaped explosive charge of the type that may be used to cut through structure of an airplane effective to form an emergency exit door, said first layer being formed from high strength and high temperature resistance carbon fiber cloth arranged to form a quasi-isotropic laminate having a thickness of about 2 mm, an area of said first layer being bonded to said structure by way of epoxy resin; a non-metallic third layer sized to substantially cover said first area and being bonded to said first layer by way of epoxy resin, said third layer being formed from high strength and high toughness aramid, or aramid-based, fiber cloth arranged to form a quasi-isotropic laminate having a thickness of about 1.5 mm; and a non-metallic second layer sized to substantially cover said first area and being bonded to said third layer by way of epoxy resin, said second layer consisting of a rubber material, wherein: said first layer, said second layer, and said third layer are configured and arranged in harmony such that said blast shield is effective to attenuate sub-effects from the detonation of said shaped explosive charge sufficient to resist damage to a human that is within a distance of about 0.4 meter of said explosive charge during said detonation. 